Capped roller chain generally comprise a standard type roller chain wherein an overlay (referred to as a cap or "roof top") spans the top of the two side bars or plates forming each link of the chain. Typically, two or more lengths of such chain extend in spaced parallel relation and are driven at the same speed. Items to be transported are placed transversely across the chain lengths and are carried thereby. In the prior art, the roof top or cap has been formed by an upper extension of one of the side bars of each link. Alternatively, metal caps have been welded to the side plates of the links.
Metal caps have the drawback of scratching or otherwise marring the surface of items being loaded thereon for transport. More recently, ultra high molecular weight polyethylene roof top caps have been provided to overcome the aforementioned problem. Such plastic caps include a steel clamp which is used in welding the caps to the side bars of the chain links.
In order to support the loads carried by the chain, the chain typically runs atop a metal support plate or channel. More recently, in order to reduce noise, plastic chain support channels have been introduced to eliminate the metal to metal contact between chain and support.